The invention relates to an apparatus for the cleaning and/or coating of a mold surface of a mold, in particular of the mold surface of a vulcanization mold for the manufacture of tires, comprising a frame which can be placed onto the mold and in which a handling device is movable along a predetermined track in such a way that at least one cleaning or coating unit is provided on the handling unit of which the relative position is adjustable relative to the mold surface, is moved past the mold surface at a predetermined spacing for the cleaning or coating, and further comprising a drive means for the adjustment of the position of the cleaning or coating unit. Furthermore, the invention relates to a method for the cleaning and/or coating of a mold surface of a mold.
The apparatus and method for the cleaning of the mold surface of a mold, in particular the mold surface of a vulcanization mold for the manufacture of tires, is known from DE 197 12 513 A1. In this apparatus a frame in which a five-axes robot is movable as a handling unit along a circular track is inserted between the part molds of the mold which can be moved apart. A nozzle for dry ice pellets is provided at the free end of the robot, and the relative position of the nozzle relative to the mold surface can be set with the aid of the robot. After the relative position has been set, the total robot, which is secured on a rotatable ring, is moved circularly, with the dry ice pellets which emerge from the nozzle cleaning the mold surface.
In this known apparatus the problem exists that as a result of the use of the robot, which takes up a lot of constructional volume as a consequence of its design, the frame must be of correspondingly large dimensions, so that the mold parts mold must be moved correspondingly far apart. Furthermore, the programming of the five-axis robot is very time and cost intensive as a result of the complex movements of the different axes, which must be coordinated with one another. A further problem in the known apparatus resides in the fact that it is exposed to high temperatures when used for the cleaning of vulcanization molds since the molds are cleaned during the running operation and consequently only cool down a little. This has the consequence that both the sensitive electronics, the drives and also the mechanical bearing points of the robot are exposed to correspondingly high operating temperatures through which their orderly operation can be disturbed. Finally, the drive with which the robot is moved in the frame must be laid out to be correspondingly powerful as a result of the masses which the robot and its drive components have, which have to be moved and braked. It is the object of the invention to so further develop the apparatus and method of the initially named kind that the handling apparatus can be programmed without great effort and an orderly operation of the handling device is possible even at high environmental temperatures.
The invention is satisfied by an apparatus having the following features. An apparatus for the cleaning and/or coating of a mold surface of a mold, in particular of the mold surface of a vulcanization mold for the manufacture of tires. The apparatus has a frame which can be placed onto the mold and in which a handling device is movable along a predetermined track in such a way that at least one cleaning or coating unit is provided on the handling device, of which the relative position is adjustable relative to the mold surface. The at least one cleaning or coating units is moved past the mold surface at a predetermined spacing for the cleaning or coating.
The apparatus further has a drive means for the adjustment of the position of the cleaning or coating unit, wherein the drive means coupled to the handling device for the adjustment of the relative position of the cleaning or coating unit is decoupled from the handling device, at least during the movement of the handling device along the predetermined track, with the cleaning or coating unit retaining its relative position with respect to the mold surface previously set by the drive device. Furthermore, the object is satisfied by a method having the following features. A method for the coating or cleaning of the mold surface of a mold, in particular of the mold surface of a vulcanization mold for the production of tires, in which a frame is positioned onto the mold, in which the relative position of a cleaning and/or coating unit held on a handling device movable along a predetermined track in the frame is subsequently adjusted with the aid of a drive means and thereafter the handling device is moved along the predetermined track, with the cleaning or coating unit being moved in its adjusted position past the mold surface for the cleaning or coating respectively. The drive means is uncoupled from the handling device after the relative position of the cleaning or coating device has been adjusted. The handling device is then subsequently moved along the predetermined track and is coupled again to the drive means for renewed setting of the relative position of the cleaning or coating unit.
In the invention the drive means is decoupled from the handling device during the movement of the handling device, while it is connected to the handling device at least during the adjustment of the cleaning or coating unit. The drive means is consequently not co-moved during the movement of the handling device in the frame, so that the drive which moves the handling device can be made correspondingly small. Furthermore, the constructional space required in the frame for the handling device is smaller in the apparatus of the invention than in the known apparatus, since the drive device which can be decoupled from the handling device need not be directly arranged in the inner space surrounded by the frame. Since the cleaning or coating unit retains its relative position previously set by the drive device with respect to the mold surface, even when the drive means is decoupled, a follow-up regulation of the position of the cleaning or coating unit during the movement of the handling device is not required, so that, on the one hand, the control complexity is smaller and, on the other hand, sensitive control modules and sensors which could be impaired in their manner of operation through the high temperatures, in particular during the cleaning of vulcanization molds, do not have to be provided at the handling device.
Further advantageous developments of the invention can be seen from the subsequent description, the drawing and also the subordinate claims. Thus, it is proposed that the handling device should be provided with a braking unit which locks the cleaning or coating unit in its relative position after the adjustment. In this way a situation is achieved in which the relative position of the cleaning or coating unit is also not misadjusted with a jolt-like movement of the handling device.
Furthermore, it is proposed that a self-locking positioning unit which is coupled with the drive means for the adjustment should be provided at the handling device, in addition to, or as an alternative to, the locking of the relative position of the cleaning or coating unit. In this embodiment the self-locking of the positioning unit also achieves a situation in which the position of the cleaning or coating unit does not change during the movement of the handling device.
In a preferred embodiment of the apparatus the drive means for the adjustment of the cleaning or coating unit is held on a carriage which is movable between a rest position, in which the drive means is spaced from the handling device, and a coupling position, in which the drive means is coupled to the handling device. With the aid of the carriage a rapid coupling on and decoupling of the drive means to or from the handling device is made possible, with the drive means being spaced from the frame when the carriage is moved into its rest position so that it is protected from high temperatures.
The handling device preferably has an attachment unit with which it is held on a rotating ring, which is rotatably mounted in the frame about an axis of rotation. During the cleaning or coating the frame is aligned relative to the mold so that the axis of rotation coincides with the axis of symmetry of the mold which is to be cleaned. Through the use of a rotatable ring, the handling device moves on a circular track, so that the handling device is particularly suited for rotationally symmetrical molds in particular, such as are, for example, used in the manufacture of motor vehicle tires.
As an alternative it is proposed that the attachment unit of the handling means should be guided in a guide provided at the frame, which forms a closed surrounding contour. In this embodiment the contour can, for example, extend in the shape of an oval, a rectangle or a polygon, so that molds with correspondingly designed mold surfaces can be cleaned or coated.
A telescopic arm which is pivotally mounted on the attachment unit is proposed as the handling device, with the pivotal position and length being adjustable with the aid of the drive means and with the cleaning or coating unit being held at the free end of the telescopic arm remote from the attachment unit. Through the use of a telescopic arm, an exact and positionally accurate setting of the position of the cleaning or coating unit can be effected without substantial technical control complexity.
In order to enable the most accurate possible alignment of the cleaning or coating unit relative to the mold surface, it is furthermore proposed that the cleaning or coating unit should be pivotally mounted on the handling device, i.e. on the telescopic arm, with the pivotal position being adjustable here with the aid of the drive means.
In a particularly preferred embodiment of the apparatus of the invention, a centering unit is additionally provided at the frame with which the frame can be aligned with respect to the mold which is to be cleaned or coated. A centering ring which is, for example, rotatably mounted on the frame, is, for example, suitable as the centering unit, with the centering ring standing in a co-operative connection with at least one lever which is pivotably mounted in the frame, such that, with one turn of the centering ring in a first direction, the lever comes into contact with the mold for alignment and, with a rotation of the centering ring in a second direction opposite to the first direction, the lever is moved away from the frame. With the aid of the centering unit the frame can be aligned in a defined position relative to the mold once it has been placed onto the mold, so that the cleaning or coating unit is moved past the mold surface during movement of the handling device without large fluctuations of the predetermined spacing.
Since correspondingly high noise emissions arise, in particular when cleaning the mold with dry ice or laser beams, it is furthermore proposed that the housing should be provided with a sound insulating jacket which at least partly surrounds the range of movement of the handling device.
The previously described apparatus can be used for the cleaning of one piece and also multi-piece molds. It is particularly suitable for the cleaning of a mold which is formed from at least two-part molds, with the part molds preferably being moveable apart from one another in an axial direction. For the cleaning or coating, the frame is moved between the part molds that should be moved apart and onto the part mold which is to be cleaned. Furthermore, the part molds can be moved together again after the insertion of the frame, with the frame being lightly clamped between the part molds. In this manner it is possible to clean or coat first the one and subsequently the second part mold in one cleaning or coating process.
If the apparatus is used for the cleaning or coating of a vulcanization mold, then it is furthermore proposed that the vulcanization mold should be kept at a temperature in a range of 140 to 175xc2x0 C., preferably in a range from 155 to 160xc2x0 C. In this way a situation is achieved in which the vulcanization mold can be directly used again for vulcanization after cleaning or coating, without the mold having to be heated up to its operating temperature again.